This invention relates generally to injection molding apparatus and more particularly to a one-piece gate and cavity insert having one or more cooling fluid flow passages extending therethrough which alternately extend both forwardly and rearwardly and inwardly and outwardly.
Injection molding gate and cavity inserts having cooling fluid flow passages which form a portion of the cavity and through which the gate extends to convey melt from a heated nozzle to the cavity are well known. For example, U.S. Pat. No. 4,622,001 to Bright et al. which issued Nov. 11, 1986 shows a two-piece insert with a cooling fluid flow passage or chamber which alternately extends radially inwardly and outwardly to improve cooling by lengthening the cooling fluid flow path and bringing the cooling fluid into closer proximity with the cavity. U.S. Pat. No. 5,443,381 to Gellert which issued Aug. 22, 1995 shows a one-piece gate and cavity insert having rib portions which cause the cooling fluid flow chambers or passages to alternately extend forwardly and rearwardly to provide improved cooling and more structural strength.
While these previous configurations are satisfactory for many applications, when molding certain materials with certain cavity configurations and sizes, it is desirable to provide even additional cooling to the cavity and the gate area.